1. Field of the Invention
The present invention relates to a device for and a method of pulsing and amplifying a singlemode laser light without harming the monochromaticity.
2. Related Art Statement
Recently, development and progression of the pulse oscillation laser are remarkably, so that the pulse laser of various ultra short time oscillations is proposed. In such a pulse laser, since an indeterminacy principle is approved between energy and time, so that the line width of the laser light becomes broaden while becoming an ultra short time oscillation, and the monochromaticity becomes worsen. By considering this respect, if the laser light from the single frequency laser with an excellent monochromaticity of the continuous oscillation is pulsed, though there is a certain limit to shorten the oscillation time, the pulsing (the optical output pulse is outputted for a short time) while maintaining the goodness of the monochromaticity, becomes possible.
As a conventional technology which pulses the laser light of the continuous oscillation, (1) a method of using a mechanical chopper, in which light is intercepted by rotating a disk with a hole so as to intercept light, except when the light is passed through the hole, and (2) a method of using an optical chopper, in which the polarizing direction of light is changed with an electro-optic (Electro Optic: EO) element and an acousto-optic (Acusto Optical: AO) element, and the phenomenon that the light does not pass a polarizer set up after these elements, are used.
However, the power of the thus obtained laser pulse light (power output) becomes lower, since the amplitude of light (strength of light) does not change before and after the pulsing when the continuous oscillation laser light is pulsed by using the above described mechanical chopper and optical chopper, and the amplification operation of the amplitude of light (strength of light) cannot be achieved.
It is an object of the present invention to eliminate the above described disadvantages of the conventional device for and method of obtaining a high powerful laser pulse light.
It is another object of the present invention to provide a device for and a method of obtaining a high powerful laser pulse light with good monochromaticity from the singlemode laser light.
According to the first present invention, there is provided a device for pulsing and amplifying a singlemode laser light comprising a singlemode laser for generating the laser light of the singlemode, an optical resonator into which the outputted laser light is introduced from the singlemode laser, and a controller for controlling the length of resonator by changing the length of the optical resonator based on a control waveform signal, which is an asymmetrical triangular repeated waveform signal, the laser pulse light of the singlemode to which optical strength is amplified from the optical resonator, is outputted by changing the length of resonator.
According to the first invention, the resonator length of the optical resonator, into which the laser light emanated from the singlemode laser is introduced, changes based on the controlling waveform signal according to the resonator length controller. The amplification of the optical power causes when the resonator length becomes a multiple of the half-wave length of the incident laser light during the change in the resonator length of the optical resonator, and the optical power (strength) becomes 0 at the rest. Therefore, the laser pulse light of the singlemode with high power can be obtained as a power output of the optical resonator.
According to the second present invention, there is provided a device for pulsing and amplifying a singlemode laser light comprising a singlemode laser for generating laser light of singlemode, an optical resonator into which the outputted laser light is introduced from the singlemode laser, an optical path interception means to intercept the optical path between the singlemode laser and the optical resonator, a resonator length controller by which the resonator length of the optical resonator is changed based on a controlling waveform signal, and a driving means for operating the optical path interception means from the leading time of the laser pulse light output from the optical resonator during the fixed time after a lapse of the given delay time, by changing the length of resonator, the laser pulse light of the singlemode to which optical strength is amplified and the trailing time is shortened, is outputted from the optical resonator.
According to the second invention, the resonator length of the light resonator into which the laser light emanated from the singlemode laser is introduced, changes based on the controlling waveform signal according to the resonator length controller. Since the amplification of the optical strength causes when the resonator length becomes a multiple of the half-wave length of the incident laser light during the change in the resonator length of the optical resonator, and the optical strength becomes 0 at the rest, the laser pulse light is output from the optical resonator. And, since the driving means operates with a certain time the optical path interception means by which the optical path between the singlemode laser and the optical resonator is intercepted from the leading time of the laser pulse light after a lapse of the given delay time. The laser pulse light of the singlemode having high power as a power output of the optical resonator and the shortened trailing time, can be obtained.
It is preferable that the controlling waveform signal is an asymmetrical triangular repeated waveform signal.
According to the above invention, since an asymmetrical triangular repeated waveform signal is used as the controlling waveform signal, by setting the resonator length so as to become a multiple of the half-wave length of the incident laser light at two places as per one asymmetrical triangular waveform signal in the process of the change in the resonator length of the optical resonator, so that the laser pulse light with a large optical strength can be obtained in the case of slow change speed of the resonator length rather than in the case of fast change speed thereof and the difference of optical strength between two laser pulse lights becomes large.
It is also preferable that a double wave generating element is provided in the optical resonator, and the laser pulse light outputted from the optical resonator is made double wave.
According to the above invention, since the double wave generating element is installed in the optical resonator, the laser pulse light output from the optical resonator can be made twice wave by the double wave generating element.
According to the present invention, there is provided a method of pulsing and amplifying a singlemode laser light comprising steps of introducing the laser light emanated from the singlemode laser into the optical resonator, and of changing the resonator length of the optical resonator based on the controlling waveform signal, which is an asymmetrical triangular repeated waveform signal, thereby outputting the singlemode laser pulse light of which optical strength is amplified, from the optical resonator.
According to the above invention, the resonator length of the optical resonator into which the laser light emanated from the singlemode laser is introduced, changes based on the controlling waveform signal, the amplification of the optical strength causes when the resonator length becomes a multiple of the half-wave length of the incident laser light during the change in the resonator length of the optical resonator, and the optical strength becomes 0 at the rest, therefore, the laser pulse light of the singlemode can be obtained with high power, as an output of the light resonator.
According to the present invention, there is provided a method of pulsing and amplifying a singlemode laser light comprising steps of: introducing the laser light emanated from the singlemode laser into the light resonator; changing the resonator length of the light resonator based on the controlling waveform signal, thereby outputting the laser pulse light from the light resonator; and intercepting the optical path between the singlemode laser and light resonator after a lapse of given delay time from leading time of the laser pulse light for a certain time, thereby outputting the singlemode laser pulse light of which optical strength is amplified, and trailing time is shortened, from the light resonator.
According to the above invention, the resonator length of the optical resonator into which the laser light emanated from the singlemode laser is introduced, changes based on the controlling waveform signal, the amplification of the optical strength causes when the resonator length becomes a multiple of the half-wave length of the incident laser light during the change in the resonator length of the optical resonator, since the optical strength becomes 0 at the rest, the laser pulse light is output from the optical resonator. Also, the optical path between the singlemode laser and the optical resonator is certain time intercepted from the leading time of the laser pulse light after a lapse of the given delay time, so that the laser pulse light of the singlemode having high power as a power output of the optical resonator and the shortened trailing time, can be obtained.
In a preferable embodiment of the method of pulsing and amplifying a singlemode laser light according to the present invention, the controlling waveform signal is an asymmetrical triangular repeated waveform signal.
According to the above invention, since an asymmetrical triangular repeated waveform signal is used as the controlling waveform signal, by setting the resonator length so as to become a multiple of the half-wave length of the incident laser light at two places as per one asymmetrical triangular waveform signal in the process of the change in the resonator length of the optical resonator, so that the laser pulse light with a large optical strength can be obtained in the case of slow change speed of the resonator length rather than in the case of fast change speed thereof and the difference of optical strength between two laser pulse lights becomes large. Therefore, this becomes advantageous to enlarge the amplification degree in the output laser pulse light.
In a preferable embodiment of the method of pulsing and amplifying a singlemode laser light according to the present invention, a double wave generating element is provided with the light resonator, thereby making the laser pulse light outputted from the light resonator wave-doubling.
According to the above invention, since the double wave generating element is installed in the optical resonator, the laser pulse light output from the optical resonator can be made twice wave by the double wave generating element.